1. Technical Field
This invention relates generally to pistons for heavy duty diesel engines, and to the method of making such pistons.
2. Related Art
Pistons for heavy duty diesel engine applications are typically either of a monobloc construction in which the piston head, pin bosses and skirt are cast of a single piece, or of an articulated construction in which the piston skirt is formed separately from the rest of the piston and joined thereto an articulated fashion through the wrist pin.
U.S. Pat. No. 4,581,983 discloses a piston of monobloc construction wherein the upper part is forged and the lower part is cast and joined at an inner face by welding with charged carrier rays with an inter layer of nickel.
U.S. Pat. No. 3,654,840 discloses a one-piece forged piston formed in a uni-axial forging process.
U.S. Pat. No. 4,910,093 discloses a method of forging a one-piece piston blank of an articulated piston. This reference has no teachings with respect to forging monobloc pistons wherein the piston skirt is an integral part of the piston structure, rather than being a separately formed, articulated component.